Trace element concentration patterns in sediments of the lower Rio Conchos, Mexico


A two-step sequential extraction of B, V, Cr, Ni, Cu, and Pb in sediments from the lower Rio Conchos, Mexico, was used to identify sections of the river where accumulation of these elements has taken place. The concentrations of Mg, Fe and Al in sediments were concurrently determined in order to infer about the possible source of trace elements. According to their extractability, B and Pb were labeled as more mobile, while Cr was the least mobile. Normalized concentration and partition coefficient (Kd) values along the lower Rio Conchos helped identify locations with abnormally large trace element values. Sites near urban centers showed the most accumulation with respect to most elements, while the highest B and Pb K(d) values were found at sites far from urban areas and irrigation drain returns. Correlation analysis between sediment and water concentrations indicated a separate concentration pattern for the sediments, most likely the result of their longer term element storing ability as compared to water. In contrast, a high correlation was obtained among elements in sediments, with the exception of B and Pb. This study is a preliminary effort to quantitatively determine the impacts of irrigation and other human activities to the quality of one of northern Mexico's most important rivers.


Geography, Geology, and Planning

Document Type





Rio Conchos, Riverbed sediments, Sequential extraction, Trace elements

Publication Date


Journal Title

Water, Air, and Soil Pollution